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Numerical modeling of a mathematical model of the cosmological evolution of an asymmetric scalar doublet with kinetic interaction between the components was carried out. A wide range of values of fundamental parameters and initial…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Yu. G. Ignsat'ev , I. A. Kokh

We investigate the possibility of future singularity due to the accelerating expansion of the Universe. It has been found that the gravitational theory comprises Ricci scalar $R$ and Gauss-Bonnet invariant $\mathcal{G}$, known as…

General Relativity and Quantum Cosmology · Physics 2023-10-18 Santosh V Lohakare , Francisco Tello-Ortiz , B. Mishra , S. K. Tripathy

The accelerated expansion of the universe together with its present day isotropy has posed an interesting challenge to the numerous model theories presented over the years to describe them. In this paper, we address the above questions in…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Z. Haghani , H. R. Sepangi , S. Shahidi

A non-minimally coupled scalar field can have, in principle, a negative effective Planck mass squared which depends on the scalar field. Surprisingly, an isotropic and homogeneous cosmological universe with a non-minimally coupled scalar…

High Energy Physics - Theory · Physics 2013-10-22 Pawel Caputa , Sheikh Shajidul Haque , Joseph Olson , Bret Underwood

We present here a brief review and discussion on recent developments in the theory of spacetime singularities. After mentioning some key motivations on the main ideas and concepts involved, we take the approach that the singularities will…

General Relativity and Quantum Cosmology · Physics 2010-10-13 Pankaj S. Joshi

Advantages of inhomogeneous cosmological models that are exact solutions of Einstein's equations over linearised perturbations of homogeneous models are presented. Examples of effects that can be described in the inhomogeneous ones are…

General Relativity and Quantum Cosmology · Physics 2011-12-05 Andrzej Krasiński

An introduction to modern theories for the origin of structure in the Universe is given. After a brief review of the growth of cosmological perturbations in an expanding Universe and a summary of some important observational results, the…

Astrophysics · Physics 2008-02-03 Robert H. Brandenberger

We predict that neutrino sources following the matter distribution of the universe result in an anisotropy in the neutrino sky imprinted by the local large-scale structure. We calculate the level of this anisotropy and explore how it…

High Energy Astrophysical Phenomena · Physics 2025-11-13 Marco Stein Muzio , Noémie Globus

We prove that a homogeneous and isotropic universe containing a scalar field with a power-law potential, $V(\phi )=A\phi ^{n}$, with $0<n<1$ and $A>0$ always develops a finite-time singularity at which the Hubble rate and its first…

General Relativity and Quantum Cosmology · Physics 2015-04-16 John D. Barrow , Alexander A. H. Graham

The accelerating expansion of the universe presents an exciting, fundamental challenge to the standard models of particle physics and cosmology. I highlight some of the outstanding challenges in both developing theoretical models and…

Astrophysics · Physics 2008-11-26 Eric V. Linder

In a landscape of compactifications with different numbers of macroscopic dimensions, it is possible that our universe has nucleated from a vacuum where some of our four large dimensions were compact while other, now compact, directions…

High Energy Physics - Theory · Physics 2012-01-11 Julian Adamek , David Campo , Jens C. Niemeyer

A self consistent effective field theory of modified gravity has recently been proposed with spontaneous breaking of local Lorentz invariance. The symmetry is broken by a vector field with the wrong-sign mass term and it has been shown to…

Astrophysics · Physics 2008-11-26 P. G. Ferreira , B. M. Gripaios , R. Saffari , T. G. Zlosnik

A theory of gravitation is constructed in which all homogeneous and isotropic solutions are nonsingular, and in which all curvature invariants are bounded. All solutions for which curvature invariants approach their limiting values approach…

General Relativity and Quantum Cosmology · Physics 2009-10-22 R. Brandenberger , V. Mukhanov , A. Sornborger

The present accelerated expansion of the universe has enriched the list of possible scenarios for its fate, singular or not. In this paper a unifying framework for analyzing such behaviors is proposed, based on generalized power and…

General Relativity and Quantum Cosmology · Physics 2019-03-07 L. Fernández-Jambrina

We give a short account of the quantisation of the Szekeres spacetime by considering the symmetries of a reduced action principle. This is an alternative approach than the one followed in the literature for the study of inhomogeneities,…

General Relativity and Quantum Cosmology · Physics 2019-12-10 Adamantia Zampeli

Oscillating solutions to the effective equations of Loop Quantum Cosmology have been suggested for the role of an `eternal seed', providing a possible starting point for the emergent universe scenario. We investigate the stability of a…

High Energy Physics - Theory · Physics 2015-06-19 Audrey T. Mithani , Alexander Vilenkin

We examine a class of braneworld models in which the expanding universe encounters a "quiescent" future singularity. At a quiescent singularity, the energy density and pressure of the cosmic fluid as well as the Hubble parameter remain…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Petr Tretyakov , Aleksey Toporensky , Yuri Shtanov , Varun Sahni

There is something missing in our understanding of the origin of the seeds of Cosmic Structuture. The fact that the fluctuation spectrum can be extracted from the inflationary scenario through an analysis that involves quantum field theory…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Daniel Sudarsky

An anthropic explanation for evident smallness of the value of the dark energy implies the existence of a time-dependent component of the scalar field, serving, together with a negative-valued cosmological constant, as one of two components…

General Relativity and Quantum Cosmology · Physics 2020-01-08 A. A. Yurova , A. V. Yurov , V. A. Yurov

We find various asymptotic limits of universes containing two interacting fluids which interact and exchange energy. We study the finite-time singularities that may develop in these cosmologies and obtain the asymptotic behaviours of the…

General Relativity and Quantum Cosmology · Physics 2013-02-20 Spiros Cotsakis , Georgia Kittou